Noun: Something insidious, evil, and/or devious designed to rip apart humanity and destroy everything we hold dear while at the same time leaving no opportunity for repair.
Can be used as an insult or compliment/observation.
Martha: wow i really hate her.
Theresa: she's just devil spawn.
Martha: i know, right?
Joe: these cookies r freakin delicious!
Not Joe: theyire devil spawn, yo!